Whole genome sequencing of Salmonella enterica serovars isolated from humans, animals, and the environment in Lagos, Nigeria.

BACKGROUND: Salmonella infections remain an important public health issue worldwide. Some serovars of non-typhoidal Salmonella (NTS) have been associated with bloodstream infections and gastroenteritis, especially in children in Sub-Saharan Africa with circulating S. enterica serovars with drug resistance and virulence genes. This study identified and verified the clonal relationship of Nigerian NTS strains isolated from humans, animals, and the environment. METHODS: In total, 2,522 samples were collected from patients, animals (cattle and poultry), and environmental sources between December 2017 and May 2019. The samples were subjected to a standard microbiological investigation. All the isolates were identified using Microbact 24E, and MALDI-TOF MS. The isolates were serotyped using the Kauffmann-White scheme. Antibiotic susceptibility testing was conducted using the disc diffusion method and the Vitek 2 compact system. Virulence and antimicrobial resistance genes, sequence type, and cluster analysis were investigated using WGS data. RESULTS: Forty-eight (48) NTS isolates (1.9%) were obtained. The prevalence of NTS from clinical sources was 0.9%, while 4% was recorded for animal sources. The serovars identified were S. Cotham (n = 17), S. Give (n = 16), S. Mokola (n = 6), S. Abony (n = 4), S. Typhimurium (n = 4), and S. Senftenberg (n = 1). All 48 Salmonella isolates carried intrinsic and acquired resistant genes such as aac.6…Iaa, mdf(A), qnrB, qnrB19 genes and golT, golS, pcoA, and silP, mediated by plasmid Col440I_1, incFIB.B and incFII. Between 100 and 118 virulence gene markers distributed across several Salmonella pathogenicity islands (SPIs), clusters, prophages, and plasmid operons were found in each isolate. WGS revealed that strains of each Salmonella serovar could be assigned to a single 7-gene MLST cluster, and strains within the clusters were identical strains and closely related as defined by the 0 and 10 cgSNPs and likely shared a common ancestor. The dominant sequence types were S. Give ST516 and S. Cotham ST617. CONCLUSION: We found identical Salmonella sequence types in human, animal, and environmental samples in the same locality, which demonstrates the great potential of the applied tools to trace back outbreak strains. Strategies to control and prevent the spread of NTS in the context of one's health are essential to prevent possible outbreaks.

Molecular surveillance of arboviruses in Nigeria.

Arboviral infections are fast becoming a global public health concern as a result of its high fatality rate and sporadic spread. From the outbreak of Zika virus in the Americas, the endemicity of Yellow fever in West Africa and South America, outbreaks of West Nile virus in South Africa to the year-round and national risk of Dengue fever in Mainland China and India. The war against emerging and re-emerging viral infection could probably lead to the next pandemic. To be above the pending possible arboviral pandemic, consistent surveillance of these pathogens is necessary in every society. This study was aimed at conducting a surveillance for Yellow fever virus, Zika virus, Chikungunya virus, Dengue virus and Rift Valley fever virus in four states in Nigeria using molecular techniques. A cross-sectional study involving 1600 blood samples collected from febrile patients in Lagos, Kwara, Ondo and Delta States between 2018 and 2021 was conducted using Real time polymerase chain reaction for detection of the pathogens. Extraction and purification of viral RNA were done using Qiagen Viral RNA Mini Kit. Samples were analyzed using One Step PrimeScript III RT-PCR mix (Takara Bio) alongside optimized primers and probes designed in-house. Positive samples were sequenced on MinION platform (Nanopore technologies). Bioinformatic and phylogenetic analysis were performed with DNASTAR Lasergene 17.3. All the RNA extracted from samples collected from the four states were negative for ZIKV RNA, RVFV RNA, CHIKV RNA and DENV RNA. However, twelve of the samples (2%) tested positive for YFV RNA. Three full genomes of sizes 10,751 bp, 10,500 bp and 10,715 bp were generated and deposited in GenBank with accession numbers: ON323052, ON323053 and ON323054 respectively. Phylogenetic analysis shows clustering within lineage 3 of West African genotype. This result shows an active spread of Yellow fever in Delta State, Nigeria. However, there is no emergence of a new genotype There is a need for an intense surveillance of Yellow fever virus in Nigeria to avert a major outbreak.

Setting research priorities for global pandemic preparedness: An international consensus and comparison with ChatGPT's output.

Background: In this priority-setting exercise, we sought to identify leading research priorities needed for strengthening future pandemic preparedness and response across countries. Methods: The International Society of Global Health (ISoGH) used the Child Health and Nutrition Research Initiative (CHNRI) method to identify research priorities for future pandemic preparedness. Eighty experts in global health, translational and clinical research identified 163 research ideas, of which 42 experts then scored based on five pre-defined criteria. We calculated intermediate criterion-specific scores and overall research priority scores from the mean of individual scores for each research idea. We used a bootstrap (n = 1000) to compute the 95% confidence intervals. Results: Key priorities included strengthening health systems, rapid vaccine and treatment production, improving international cooperation, and enhancing surveillance efficiency. Other priorities included learning from the coronavirus disease 2019 (COVID-19) pandemic, managing supply chains, identifying planning gaps, and promoting equitable interventions. We compared this CHNRI-based outcome with the 14 research priorities generated and ranked by ChatGPT, encountering both striking similarities and clear differences. Conclusions: Priority setting processes based on human crowdsourcing - such as the CHNRI method - and the output provided by ChatGPT are both valuable, as they complement and strengthen each other. The priorities identified by ChatGPT were more grounded in theory, while those identified by CHNRI were guided by recent practical experiences. Addressing these priorities, along with improvements in health planning, equitable community-based interventions, and the capacity of primary health care, is vital for better pandemic preparedness and response in many settings.

Typhoid Fever: Tracking the Trend in Nigeria.

Typhoid fever continues to pose a serious health challenge in developing countries. A reliable database on positive blood cultures is essential for prompt interventions. To generate reliable data on Salmonella enterica serovar Typhi (S. Typhi)-positive blood culture trends in typhoidal Salmonella in Nigeria alongside changing contextual factors and antimicrobial resistance patterns, a retrospective cohort study was conducted in two hospitals in Lagos between 1993 and 2015. Medical records of typhoid patients were reviewed for positive culture and antibiogram, using standard procedures and analyzed. Additional data were retrieved from a previous study in seven facilities in Abuja and three hospitals in Kano from 2008 to 2017 and 2013 to 2017, respectively. A declining trend in percent positivity of S. Typhi was observed in Abuja with more erratic trends in Lagos and Kano. In Lagos, more than 80% of the isolates from the entire study period exhibited multiple drug resistance with a generally increasing trend. Of the chosen contextual factors, improvements were recorded in female literacy, access to improved water supply, diarrheal mortality in children younger than 5 years, gross domestic product, and poverty while access to improved sanitation facilities decreased over time nationally. Typhoid fever still poses a serious health challenge in Nigeria and in antibiotic resistance, and is a major health security issue. A combined approach that includes the use of typhoid vaccines, improvements in sanitation, and safe water supply is essential.

A retrospective study of community-acquired Salmonella infections in patients attending public hospitals in Lagos, Nigeria.

INTRODUCTION: A retrospective cohort study on Salmonella-associated diseases (SADs) was conducted in 14 public hospitals across Lagos State, Nigeria, between 1999 and 2008. METHODOLOGY: Medical records of clinically diagnosed patients with confirmed Salmonella infections were reviewed for the 10-year period. Laboratory diagnosis of typhoid fever cases in all the hospitals were first based on Widal agglutination tests then followed by culture, while non-typhoidal Salmonella infections were based on culture technique. RESULTS: A total of 85,187 confirmed cases of SADs were found, of which 880 deaths were recorded (case-fatality rate = 1.03% / 10 years). The mean incidence of SADs in Lagos State for the 10-year period was estimated at 45 cases per 100,000 persons/year, while that of typhoid fever alone was 16 cases per 100,000 persons/year. During the studied period, the number of deaths due to typhoid fever was significantly (P < 0.05) higher than deaths due to gastroenteritis except in 2003 and 2004. Risk associated with typhoidal deaths was 4 to 11 times greater when compared to gastroenteritis deaths between 2000 and 2002. Salmonella-associated diseases were most prevalent in adults 21 to 30 years of age (49.49%). Cases of patients with invasive Salmonella-associated gastroenteritis were observed mainly in children under five years of age. CONCLUSION: The current surveillance data indicated high incidence of SADs in areas exposed to environmental contaminations. This study revealed that infections caused by Salmonella enterica serovars are endemic in our environment thus poses a serious threat to public health. Constant public health education is essential to avert undue epidemics.

Application of phage typing and pulsed-field gel electrophoresis to analyse Salmonella enterica isolates from a suspected outbreak in Lagos, Nigeria.

INTRODUCTION: Inadequate potable water supply and poor sanitation predispose to food- and water-borne diseases associated with Salmonella enterica serovars in developing countries. In this study the possible source of an unprecedented upsurge of Salmonella-associated community gastroenteritis was traced using both phage-typing and pulsed-field gel electrophoresis (PFGE). METHODOLOGY: Nineteen Salmonella Typhimurium (three sporadic isolates included) and 13 Salmonella Enteritidis isolates from clinical, animal, and environmental samples were subjected to antimicrobial susceptibility testing, phage-typing, and PFGE analysis using standard procedures. RESULTS: Eleven (68.8%) of the 16 outbreak-related multidrug resistant S. Typhimurium belonged to DT 71 phage type with cluster PFGE type X3, representing the most prevalent strain identified among human, animal, and environmental isolates. The remaining five (31.2%) outbreak-related strains  reacted but did not conform with clear phage types (RDNC) with cluster PFGE types X1 and X2 (96.8% similarity). Sporadic strains were untypable and belonged to X4 PFGE type. However, the evaluated S. Enteritidis strains that were multidrug resistant without a definite phage type belonged to PFGE cluster type X1e and were identified among the water and human strains. None of the Typhimurium and Enteritdis isolates was resistant to the fluoroquinolone antibiotics that were evaluated. CONCLUSION: This study emphasizes the epidemiological usefulness of PFGE typing in the detection of emerging strains of multipledrug resistant Salmonella, particularly S. Typhimurium DT71, that pose serious health implications in our environment. The study provides epidemiological links between environmental reservoirs and human infection in this community.